Winter Pests in Your Pantry

ASK A SPECIALIST: I FOUND BUGS AND WEBBING IN MY BOX OF CEREAL. WHAT SHOULD I DO?

Pantry pests are usually brought into the home in prepackaged foods and grains for food storage. Pet and animal foods, including grains and seeds for chickens and song birds, can also be the source of insect infestations in the home and storage areas.

The most common insect pests in the home pantry are small beetles and moths. The Indian meal moth and sawtoothed grain beetle are two of the most common in Utah. If you find insects, their shed skins, webbing, sawdust-like frass (insect waste), broken grain kernels or other signs of insect contamination in stored grain and food products, you may have an active insect infestation. Consider these tips to alleviate pantry pests.

The first and most important step is prevention. Inspect grain-based foods, including animal foods, for insect infestation immediately after purchase and then periodically during storage. Only buy the amount of grain products you can use within a two-month period. For longer-term storage, store whole rather than ground or processed grains, and only grind the amount you need for a week or so. Store grains in air-tight, rigid plastic or metal containers. Insects can chew through paper, plastic and foil bags. Follow the “first in-first out rule” when stocking your food pantry and use older foods first. Clean up food and grain spills in the kitchen, and remove crumbs and food particles in food storage areas. Vacuum regularly, and clean pantry shelves with a disinfectant. Keep stored foods in only a few designated areas in the home to reduce potential sites for colonization and the spread of insects.

If contaminated foods are found, check all food products that have the potential for insect infestation, and remove infested foods from the pantry. If the foods do not have significant value, the easiest clean-up method is to remove and dispose of them. If infested products are valuable, a heat or cold treatment can be used to kill the insects. To heat, spread grain products on a tray and heat in the oven at 130 to140 F for 30 to 60 minutes. Heating whole or processed grain may alter its characteristics and may not be economical when considering the cost of energy used versus replacement. Do not heat finely ground grains such as flour due to the danger of fire or explosion in the oven. Alternatively, freeze food products at 0 F or lower for 4 to 7 days to ensure that the entire contents are thoroughly frozen. Both heating and chilling as described should be adequate to kill all insect life stages, including eggs and pupae.

Are insects and contaminated foods harmful to eat? Generally, they are not. Pantry insect pests do not contain toxins or diseases that are harmful to humans. However, insect activity in stored food products can introduce and spread molds and bacteria. Insect and decay-damaged foods can develop off-colors, flavors and odors. Infestations may also reduce the nutritional quality of the food product. Therefore, if the infestation is severe, it is usually best to discard the food.

To find fact sheets and other information about pantry pests and home and garden pests, visit the Utah State University Extension Utah Pests website at www.utahpests.usu.edu.